The present clinical trial is conducted in four parts. Part A consists of safety and tolerability studies in 4 cohorts of 3 healthy subjects who are administered a single dose of three escalating concentrations of the drug and placebo intra-nasally. Part B consists of safety & tolerability as in part A but with multiple doses (3 doses/day for 5 days). Part C comprises of safety/tolerability as well as efficacy studies in chronic kidney disease patients stable on dialysis who are nasal carriers of S.aureus or MRSA on a treatment regimen as in Part B. Part D comprises of safety and efficacy studies in any patient who are nasal carriers of S.aureus or MRSA with single dose of 3 escalating concentrations of the drug and placebo intra-nasally.